Problem with MP hollow point mold.

[maximus]

Hey guysI have a problem with my new mold the first time they came out wonderfully. Now this time the tip of the hollow point won't fill up completely like in the rim of the hollow point there is a spot where there is a low wall on the rim.

[OS OK]

More heat in the mould and especially the pins needed.

[Jags93]

Try heating up the pins with a little torch. The pins take longer to get to full temp and drop heat faster than the body of the mold.

You should expect a higher number of rejects over a regular mold.


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[cwlongshot]

100% what the guys have told ya.

I set my mold directly on top of my pot for a good 20-35 minutes before pouring. (As pot warms up) THEN make first pour and PUT IT BACK UP THERE FOR A FEW MORE!! I fully expect to toss the first few drops too. Then things should be hot for making good bullets.

Pretty much three things ruin a casting. Contaminates on the mold, Contaminates within the alloy and not enough heat in the mold. Check & adhere to these all these and most of the time you will be in for a smooth casting session.

Good luck


CW

[winelover]

Heat that mould up on a hot plate. I leave my moulds on the hot plate the whole time, I'm waiting for the alloy to melt. Ladle pouring, also helps. Especially, to keep the mould up to temperature. Providing, you use a large capacity ladle. I use a Rowel #2...............holds two pounds of molten lead. Keep pouring, leaving the excess flow back into pot, until it's empty.

I used a MP 44-250 cup point, two cavity mould the other day. I poured 155 perfect bullets, though only half a dozen back, after the mould was up to temperature.............after a couple of cycles.

Winelover

[farmbif]

ive had that with the large round and penta point ., if it's not too big I just shoot em anyway. when the mold and pins get good and hot and there is enough tin added into my wheel weight mixture the voids go away. I like my bullets to be on the frosty side anyway, makes the lube stick better it seems

[DHDeal]

Hot plate the mold until the alloy is up to temp then cast away. I believe what you're descibing is just the HP is not filling out well. When my MP Molds get "seasoned", I can often get good bullets after the first couple pours if the pins and sprue plate are hot.

[cwlongshot]

The use of a Hot is nice. It absolutely does the job. Any who argue that are not worth arguing with. :lol:

BUT, Newbies, PLEASE, Dont for a second feel it is a requirement. If You have a electric pot. You HAVE A HEATER. In over thirty years meltin lead I never once felt lacking in not using a hot plate.

CW

[DHDeal]

I always say/type the same thing as I try for consistency even in giving helpful hints. My hot plate advice is due to the fact I've never used an electric pot. You make a good point about if you have an electric pot it'll work double duty as a mold heater.

My learning curve was with single cavity BIG bullets for my 45 2/10" and there were sessions I fought for those perfect bullets. Didn't know why and had no one to ask. This was 2001ish and the internet was relatively new and there was no Castboolits site that I was aware of. If I'd have known how important the mold and sprue plate temp was to perfect bullets I'd have been a happy camper. We're lucky as it's simple to ask questions from very experienced casters who have traveled that road already. I know what I'm doing, but still pick up tricks all the time and I appreciate it!

[tomme boy]

Also coat the pins with a lead pencil or moly. I have a spray can of moly that I use on the pins. Usually recoat them every 500 bullets or so.

[Walks]

I started using a Hot plate about 40yrs ago.
This was after casting on my own for about 7yrs.
Made all the difference. Usually got good bullets after 2 or 3 pours.
Dad was right. He always used one.
Great way to keep your molds hot as you wait for it to come up to casting temp after filling it up with fresh ingots. Preheat ingots for that refill too.

[winelover]

Hot plate isn't a requirement...........I used a propane torch, for over thirty years, to preheat my moulds. However, it must be used judiciously, or risk warpage.

Winelover

[OS OK]

A good hotplate will make even a troublesome mould comply & be quick about it. One of the biggest little secrets in casting is temperature, that is obvious, temp. of the melt and the moulds.

If you can get your moulds to 325º to 400º prior to the first cast, I guarantee success by the 3'rd mould drop...depending on the material the mould is made from and the mass of the mould itself, they all require a little different amount of heat. They bleed off the extra heat you pour into the mould at different rates also, that rate will set your cadence of pouring & cracking that sprue to get a smooth base.
If your getting a tearout of some material from under the sprue hole, you need to give the mould a few seconds more for the melt to freeze in the cavity...then cut sprue. Be observant of what your doing and diagnose any symptom/flaw your having on the fly...don't blindly keep pouring and whacking like a man with a mission, determine what the problem is and correct as you cast.
A simple tin can over an old skill saw blade sitting on the hot plate will make a mould oven & a $6 BBQ temp. gauge will monitor the temperature in the oven. Yah, it's not necessary for all this extra equipment but we all go about our casting a little different from each other...I am the curious type and I like empirical evidence of the variables...I would rather know than use a hit & miss approach, it's just simpler that way for me.

This setup works well for me...a small tray to catch the sprue cuts on the left and the right with a folded towel on a small piece of wood makes a good drop ramp so as not to damage your delicate castings when they come out of the mould so hot...gives a soft spot to land and roll into the pile so they don't land on each other and damage the HP cavities or nick each other up on the drive bands and noses.

https://i.imgur.com/PvDO92L.jpg

If you use the older single cavity HP moulds, you can preheat the pins by putting a couple holes in the top of the can to stick the pins in.

https://i.imgur.com/mMA80yC.jpg

Be as creative as you like, this old bucket bale serves as a support for the handles so they don't topple out of the garage as they heat up.

https://i.imgur.com/TmqUru1.jpg

The nicest thing about this system is that you can get interrupted while casting, set the mould back into the oven and pick up where you left off when you had to walk away for a short time. (I would advise never walking very far from a hot pot of lead...not ever or at least until someone hangs ole'Murphy.)